Beginning in 1976 CSL developed and installed eleven Laboratory Data Acquisition and Control System (LDACS) computer systems throughout Building 2. Based on Digital Equipment Corporation (DEC) LSI-11 micro-computers, the LDACS computers were connected to laboratory instruments for control and data collection. Collected data were then transferred to a central computer over low-speed serial lines for further processing. CSL plans to replace the four LDACS computers still in routine use for which commercial equivalents systems are not available with a mix of IBM PC and Apple Macintosh computers. The new systems will perform the same functions as the LDACS but will be connected to the building Local Area Network (LAN). The new computers will be equipped with equipped with the appropriate interface components to control the laboratory instruments. The current range of desktop computers are considerably less expensive ($5-10K), offer more performance and ar potentially less difficult to program than the original LDACS. The software will be modular: small programs to perform minimal tasks (i.e. temperature measurement) invoked from a general user interface program. The user interface will have a high degree of compatibility with the existing LDACS system and user screens will be easily modified. CSL plans to replace two LDACS in the current FY. The first unit, a Perkin Elmer 580B infrared spectrophotometer is now in use with the new PC interface. The second unit, a CARY 210 UV spectrophotometer is under development. It is anticipated that this system will be general enough for use in other research labs at NIH.